JP5270999B2 - Magnetic coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic coupling in simple structure, which reduces coupling loss that arises by a drive shaft and a driven shaft attracting each other by opposite magnets. <P>SOLUTION: In the magnetic coupling, in which first magnet bodies that become mutually attracting polarity are held at magnet holders on a drive shaft and a driven shaft that are provided in opposition across a bulkhead consisting of a nonmagnetic substance, each magnet holder includes a second magnet body, and also at least a part of it is structurized so that the distance to the bulkhead may be larger according as it goes away radially, with the axis on the bulkhead side of the drive shaft or the driven shaft as its apex, thereby making it hold a magnetic viscosity elastic fluid, thus it is so arranged as to generate thrust direction stress in a direction of breaking the drive shaft and the driven shaft away each from the bulkhead by the magnetic force of the magnet holder and the surface tension and the centrifugal force of the magnetic viscosity elastic fluid that rotates accompanying the rotation of the magnet body holder. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a magnetic coupling. In particular, the present invention relates to a magnetic coupling, and a drive shaft and a driven shaft that are provided opposite to each other with a partition made of a non-magnetic material at a predetermined distance from the center of the drive shaft. The present invention relates to a magnetic coupling that can reduce an axial load generated when a driving shaft and a driven shaft are attracted to each other by opposing magnets.

  The magnetic coupling is a driving force transmission mechanism that uses the attractive force and repulsive force of a magnet to transmit the driving shaft side driving force to the driven shaft side in a non-contact manner. In this magnetic coupling, since the driving shaft and the driven shaft are not in contact with each other, the driving force can be transmitted even when the driven shaft side is completely isolated from the outside. For this reason, there is a possibility that gas or substance may enter or leak when the driven shaft side is penetrated through the shaft, such as in a high pressure or vacuum state, in a container containing extremely toxic substances or radioactive substances, or an artificial heart This is a driving force transmission mechanism that is suitable for use in the case where an accident may occur if blood flows to the motor side.

  As a prior art in which a driving force is transmitted to a driven shaft provided in such a sealed container by magnetic coupling, for example, a driving force transmission mechanism to a fluid control valve disclosed in Patent Document 1 is provided. is there. In the technique disclosed in Patent Document 1, a pair of magnetic couplings sandwiching a partition wall constituting a sealed valve box, providing a motor on the outside of the valve box, and facing the driven shafts provided on the inside of the valve box with each other. In addition to driving, springs are provided in the axial direction of the motor shaft and the driven shaft inside the valve box, respectively, and the driving shaft and the driven shaft are elastically supported by pressing them against the partition wall, respectively, and the inertial force immediately after the operation stops The generation of vibrations and noise caused by the above is prevented, and the life of the drive motor and mechanical parts due to the vibrations is prevented from being reduced.

JP-A-10-78152

  However, in the driving force transmission mechanism disclosed in Patent Document 1, a force in the direction in which the motor shaft and the driven shaft are attracted to each other is also applied by magnetic coupling, and each of the motor shaft and the driven shaft is moved to the partition side by a spring. Since it is pressed, even if lubricating oil is used, rotational energy is consumed by contact between the shaft and the partition wall. In addition, wear may occur and seizure may occur. In order to prevent this, some thrust bearings are provided that are fixed on the thrust side so that the shaft ends do not come into contact with the bulkheads. In this case, too, the force in the thrust direction is applied to the bearing by the attractive force of the magnetic coupling. As a result, frictional force is generated and coupling loss occurs.

  Therefore, in the present invention, it is possible to reduce the coupling loss, that is, the axial load, which is caused by the attracting of the driving shaft and the driven shaft to each other by the opposing magnet or the magnetic body and the magnet with a very simple configuration. The challenge is to provide magnetic coupling.

In order to solve the above problems, the magnetic coupling according to the present invention is:
A drive shaft and a driven shaft that are opposed to each other across a partition wall made of a non-magnetic material and are arranged on an axis,
A plurality of first magnet bodies that are arranged at a predetermined distance in the radial direction from the shaft center of each of the drive shaft and the driven shaft and that are opposed to each other as polarities attracting each other, and each of the drive shaft and the driven shaft In a magnetic coupling comprising a magnet body holding portion that is provided and holds the first magnet body,
A second magnet body disposed in a region around the axial center in each of the magnet body holding portions; and a magnetic viscoelastic fluid held by the magnetic force of the second magnet body, and the magnet body holding portion. Is formed so that the separation distance from the partition wall increases as the distance from the partition wall side axis increases at least partially in the radial direction.
The magnet body holding portion, and one end of the partition wall-side axis, is formed in an arc shape in the circumferential direction, the centrifugal force of the magnetic viscoelastic fluid by rotation of the magnet holding member and the surface tension and the second magnet Due to the resultant force with the magnetic force of the body, a low-axis load is applied due to the thrust direction stress in the direction in which the drive shaft and the driven shaft are separated from the partition wall against the pulling force of the first magnet body. It is characterized by.

Similarly, the magnetic coupling according to the present invention is
The drive shaft and the driven shaft, which are opposed to each other with a partition made of a non-magnetic material interposed therebetween, attract each other at a predetermined distance in the radial direction from the shaft center of each of the drive shaft and the driven shaft. Magnetic coupling comprising a plurality of first magnet bodies arranged in a relative relationship as polarities, and a magnet body holding portion that is provided on each of the drive shaft and the driven shaft and holds the first magnet body In
A magnetic viscoelastic fluid held by a magnetic force in the region around the axial center of the magnet body holding portion;
Each of the magnet body holding portions is configured such that the separation distance from the partition wall increases as the distance from the partition wall increases in the radial direction with the partition wall side axis as an apex at least partially. Is formed in an arc shape in the circumferential direction, and is configured to generate a magnetic force by the first magnet body in the region around the axis using a magnetic body,
Against the attractive force of the first magnet body due to the resultant force of the centrifugal force and surface tension of the magnetic viscoelastic fluid due to the rotation of the magnet body holding part and the magnetic force of the area around the axis of the magnet body holding part. The drive shaft and the driven shaft that are generated are each made to have a low axial load by a thrust direction stress in a direction in which they are separated from the partition wall.

  As is generally known, a magnetic viscoelastic fluid is a mixture of a magnetic fluid and a viscoelastic fluid. Among them, the magnetic fluid is interfaced with the surface of a ferromagnetic fine particle such as ferrite having a particle diameter of about 10 nm. A black opaque colloidal solution in which an active agent is adsorbed and stably dispersed in a solvent. The other viscoelastic fluid is a non-Newtonian fluid that has both viscous and elastic properties. When the shear deformation is caused by rotation due to the elasticity of the polymer liquid, normal stress (rotational direction (radial direction) Direction), that is, a stress in the thrust direction).

  Therefore, the magnet viscoelastic fluid is held in the magnet body holding portion by the magnetic force generated by the second magnet body or by the magnetic force generated in the region around the axis of the magnet body holding portion by the first magnet body. When the holding surface is rotated, stress in the direction perpendicular to the rotation direction (thrust direction) is generated by the normal stress effect in the viscoelastic fluid, reducing the contact force between the drive shaft and the partition wall of the driven shaft (low-axis load). Since the magnetic force generated by the second magnet body or the magnetic force generated in the region around the axis of the magnet body holding portion by the first magnet body also acts as a coupling, the cup has a very simple configuration. A magnetic coupling that can reduce ring loss can be provided.

  The magnetic viscoelastic fluid is set such that the resultant force of the surface tension and the magnetic force of the second magnet body is greater than the resultant force of the centrifugal force and gravity generated by the rotation of the magnetic viscoelastic fluid, Further, in the magneto-viscoelastic fluid, the resultant force of the surface tension and the magnetic force in the region around the axial center in the magnet body holding portion is larger than the resultant force of centrifugal force and gravity generated by the rotation of the magneto-viscoelastic fluid. By being selected as such, the magnetic viscoelastic fluid can be continuously held in the magnet body holding portion.

  Furthermore, the magnet body holding portion can be formed (worked) very easily by forming a conical shape with the partition wall side axis as the apex.

  The magnet body holding portion is formed in an arc shape in the circumferential direction with the partition wall side axis as one end, so that the magnetic viscoelastic fluid is held at an annular portion at a predetermined distance from the drive shaft and the driven shaft. In this case, the centrifugal force of the magnetic viscoelastic fluid becomes the stress in the thrust direction, and the contact force between the drive shaft and the partition wall of the driven shaft can be reduced.

  In addition, if the magnet body holding portion is brought into contact with the partition wall at a plurality of positions including one or an annular portion in a non-rotating state, the driving shaft and the driven shaft are stable even in a non-rotating state. Can be stopped.

  In addition, the position where the magnet body holding portion is in contact with the partition wall in the non-rotating state is the partition wall side axis so that the drive shaft and the driven shaft are stable even when the driving shaft and the driven shaft are rotated from the non-rotating state. And can be rotated.

  Further, the magnet body holding portion is formed in an arc shape with the partition side axial center as one end, and the portion where the magnet body holding portion contacts the partition wall when the driving shaft and the driven shaft are not rotated, If it is provided in the arcuate annular portion, the driving shaft and the driven shaft can be in a stable state regardless of whether they are in a non-rotating state or a rotating state.

  As described above, the magnetic coupling according to the present invention is magnetically coupled to the magnet body holding portion formed so that the separation distance from the partition increases as the distance from the partition increases in the radial direction, with at least a part of the partition side axis as the apex. By holding the viscoelastic fluid, a stress in a direction perpendicular to the rotation direction (thrust direction) is generated by the normal stress effect, and the contact force between the drive shaft and the partition wall of the driven shaft is reduced by the thrust direction stress. Therefore, it is possible to provide a magnetic coupling that can transmit a driving force efficiently and have a long life with a very simple configuration and reduced coupling loss and a low axial load.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  1A is a schematic diagram of a main part of the magnetic coupling according to the first embodiment of the present invention, and FIG. 1B is an example of an arrangement state of a magnet body for torque transmission (first magnet body). FIG. 2 is a schematic view of an enlarged configuration of a magnet body holding portion that holds a magnetic viscoelastic fluid in Example 1 of the magnetic coupling according to the present invention, and FIG. It is a figure for demonstrating the principle which produces the thrust direction stress of the direction which separates a drive shaft and a to-be-driven shaft from a partition, respectively.

In the figure, 10 is a magnetic coupling of the present invention, 11 is a driven shaft, 12 is a driving shaft such as a motor, 13 and 14 are magnet body holding portions (cones) for holding magnet bodies constituting the magnetic coupling, 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , 16 ₂ are magnet bodies (hereinafter referred to as first magnet bodies) constituting a magnetic coupling, 17 is a magnetic viscoelastic fluid, 18 is a partition wall, and 19 is a driven shaft. , 20 is a rotation direction of the drive shaft, and 26 is a magnet body (hereinafter referred to as a second magnet body) for holding the magnetic viscoelastic fluid.

  The magnet body holding portions (cones) 13 and 14 are made of a non-magnetic material such as stainless steel when the second magnet body 26 is disposed in the axial center peripheral region. The magnet body holding portions (cones) 13 and 14 are at least partly centered on the partition 18 side axis of the drive shaft 12 and the driven shaft 11 as shown in FIG. 2A. The distance from the partition wall 18 increases as the distance increases in the radial direction. In the first embodiment, a conical shape is used.

  Returning to FIG. 1, it is preferable that the angle between the cone-shaped portions of the magnet body holding portions (cones) 13 and 14 and the partition wall 18 is about 3 ° as shown. In the case of the first embodiment, the magnetic viscoelastic fluid 17 is held by the magnetic force of the second magnet body 26 in the gap between the cone-shaped portion and the partition wall 18 in the magnet body holding portions (cones) 13 and 14. It is like that.

As shown in FIG. 1B, the first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , and 16 ₂ constituting the magnetic coupling are separated from the axis of the drive shaft 12 and the driven shaft 11. A predetermined distance (90 degrees in FIG. 1B) is provided at a predetermined distance in the radial direction. The partition wall 18 is made of stainless steel, resin, ceramic, or the like, and the first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , 16 ₂ sandwich the partition wall 18 and are opposed to each other. So that one of the first magnet bodies 15 ₁ , 16 ₁ is an N pole, the other is an S pole, and the other one of the first magnet bodies 15 ₂ , 15 ₂ is an N pole, the other is They are arranged on the south pole and attract each other. The first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , and 16 ₂ are configured such that one is a magnet and the other is a magnetic body such as iron, and the magnetic body is attracted by the magnetic force of one magnet. A magnetic coupling may be configured.

As is generally known, the magnetic viscoelastic fluid 17 is a mixture of a magnetic fluid and a viscoelastic fluid. Among these, the magnetic fluid is, for example, product number W-41 of Taiho Kozai Co., Ltd. Further, a black opaque colloidal solution in which a surfactant is adsorbed on the surface of a ferromagnetic fine particle such as ferrite having a particle diameter of about 10 nm and is stably dispersed in water as a solvent. The other viscoelastic fluid is a non-Newtonian fluid such as Polyacrylamide (PAA) having both viscous and elastic properties. X10 ⁷ and a concentration of about 7500 ppm are used.

  Further, as shown in FIG. 2A, the magnet body holding portions (cones) 13 and 14 have magnetic force by the second magnet body 26 for holding the magnetic viscoelastic fluid, so that the magnetic viscoelasticity is obtained. The fluid 17 is held in the gap between the magnet body holding portions (cones) 13 and 14 and the partition wall 18 so that even if the magnetic viscoelastic fluid 17 is rotated by the rotation of the driven shaft 11 and the driving shaft 12, the fluid 17 is not scattered. ing.

  A magnetic viscoelastic fluid, which is a mixture of magnetic fluid and viscoelastic fluid, generates normal stress (perpendicular to the rotation direction) in addition to shear stress when the shaft or magnetic viscoelastic fluid holding surface is rotated to cause shear deformation. In a different direction, that is, a stress in the thrust direction). Such a phenomenon does not occur in the case of pure viscosity.

  Further, the magnetic viscoelastic fluid 17 is rotated with the magnetic coupling 10 placed horizontally as shown in FIG. 2B, which is an enlarged view of a portion denoted by reference numeral 27 in FIG. 2A. When it is made, centrifugal force 21 and gravity 22 act. Therefore, the resultant force of the surface tension 23 of the magnetic viscoelastic fluid 17 and the magnetic bulk force (magnetic force) 24 of the second magnet body 26 for holding the magnetic viscoelastic fluid is the centrifugal force 21 and the gravity 22. By selecting so as to be larger than the resultant force, scattering of the magnetic viscoelastic fluid 17 can be prevented.

  Further, when the magnet body holding portions (cones) 13 and 14 are rotated at a high speed and the magnetic viscoelastic fluid 17 is also rotated together, a stress in the thrust direction indicated by 25 is generated by the normal stress effect described above, and the magnet body holding portion ( Since the cones 13 and 14 are pressed in the direction opposite to the partition wall 18, the driving shaft 12 and the driven shaft 11 receive thrust stress in the direction of separating from the partition wall 18, and the contact force with the partition wall 18 is reduced. It is possible to provide a low-axis load magnetic coupling that can reduce coupling loss with a very simple configuration.

In order to reduce the contact force between the drive shaft 12 and the driven shaft 11 with the partition wall 18, the second magnet for holding the magnetic viscoelastic fluid 17 for holding the magnetic viscoelastic fluid 17. The resultant force of the magnetic force of the body 26 and the thrust direction stress 25 separates the drive shaft 12 and the driven shaft 11 (magnet body holding portions 13, 14) from the partition wall 18, and the first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , 16 ₂ need to be balanced at a certain point.

  By doing so, a thrust bearing and a mechanism for pressing each of the motor shaft and the driven shaft against the partition wall by a spring as shown in Patent Document 1 are unnecessary, and the shaft (magnet body holding portion 13) is not required. 14) and the bulkhead contact with each other, a low-axis load magnetic coupling that reduces coupling loss with a simple configuration without causing rotational energy consumption, wear, and seizure. It becomes possible to provide.

  FIG. 6 is a schematic configuration of an experimental apparatus for measuring the thrust direction stress in the direction of separating the drive shaft 12 and the driven shaft 11 from the partition wall 18 of the magnetic coupling 10 according to the present invention. It is the graph of the rheological characteristic measured by the experimental apparatus shown in FIG.

  In the figure, 61 is a servo motor, 62 and 63 are pulleys and timing belts for transmitting the driving force of the servo motor 61 to the magnetic coupling, 64 is a torque meter, 65 is a rotating meter, 66 is a magnetic coupling, and 67 is a magnetic coupling. The magnetic viscoelastic fluid described above, 68 is a partition, 69 is a thrust sensor that measures a stress in the thrust direction, 70 is a dynamometer, 71 is an A / D converter, and 72 is a computer that accumulates measurement results.

The test fluid used in this experiment is the product number W-41 of Taiho Kouzai Co., Ltd., the magnetic fluid described above, the density is 1.416 [kg / m ³ ], and the viscosity is 1.8 × 10 ⁻² [ Pa · s], saturation magnetization 30.2 [Wb / m ² ], average particle diameter 10 ⁻⁸ [m], volume concentration 10.90 [%], magnetic moment 21.3 [Wb · m / kg], One particle volume is 5.24 × 10 ⁻²⁵ [m ³ ], and the number density is 2.06 × 10 ²³ [pieces / m ³ ]. A viscoelastic fluid having a molecular weight of about 1.6 × 10 ⁷ and a concentration of 7500 ppm, such as the name “Sanfloc AH-210P” of Sanyo Chemical Industries, Ltd., was used.

On the other hand, the first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ and 16 ₂ for torque transmission in the magnetic coupling are neodymium magnets having a residual magnetic flux density of 380 mT, and the distance between the magnet bodies is 5 mm. The torque transmission capacity was 0.55 Mn. As the second magnet body 26 for holding the magnetic viscoelastic fluid, neodymium magnets and ferrite magnets having residual magnetic flux densities of 445 mT and 130 mT were used. The magnet body holding portions (cones) 13 and 14 were made of SUS304 having a thickness of 1.5 mm, and the angle with the partition wall 18 in the conical shape portion was set to about 3 °. The partition wall 68 is SUS304 having a thickness of 1.5 mm.

  FIG. 7 is a graph of rheological characteristics measured by the experimental apparatus shown in FIG. The horizontal axis of the graph in FIG. 7A is the shear rate (sheer rate γ: rotation speed) [1 / s], the vertical axis is the viscosity (viscosity η) [Pa · s], and the shear rate (sheer It can be seen that the viscosity (viscosity η) decreases as rate γ) increases. In the graph of FIG. 7B, the horizontal axis is a shear rate (sheer rate γ) [1 / s], the vertical axis is N1 (normal stress in a direction perpendicular to the rotation direction) [Pa], and the shear rate ( It can be seen that N1 (normal stress in the direction perpendicular to the rotation direction) increases as sheer rate γ) increases. That is, it can be seen from the graph of FIG. 7A that the viscosity decreases as the shear rate increases, and from the graph of FIG. 7B, the normal stress increases as the shear rate increases. Recognize.

  The above is the magnetic coupling according to the present invention. The present invention is not limited to the form of the first embodiment shown in FIG. 1, and various modifications are possible. First, FIG. 3 is a schematic diagram of the configuration of the magnet body holding portion of the second embodiment of the magnetic coupling according to the present invention.

  The magnetic coupling shown in FIG. 3 has the magnetic viscoelastic fluid holding portions 35 and 36 of the magnet body holding portions (cones) 33 and 34 as one end at the partition 18 side center between the drive shaft 12 and the driven shaft 11. The arc is formed in the circumferential direction. In this way, the arc-shaped magnetic viscoelastic fluid holding portions 35 and 36 have an annular shape on the outer edge side of the magnetic viscoelastic fluid holding portions 35 and 36, and if the magnetic viscoelastic fluid 17 is held even in the annular portion, This time, the centrifugal force of the magneto-viscoelastic fluid 17 becomes a stress in the thrust direction, and further, the contact force between the drive shaft 12 and the partition wall 18 of the driven shaft 11 can be reduced.

  In addition, when the magnet body holding portions (cones) 33 and 34 are not rotating (non-rotating state), it is general that the apex of the magnet body holding portions (cones) 33 and 34 is in contact with the partition wall 18. However, when there are annular portions in the magnetic viscoelastic fluid holding portions 35 and 36 as described above, the drive shaft and the driven shaft are not rotated by providing a portion in contact with the partition wall 18 in the annular portion. In either the state or the rotation state, it can be made stable.

FIG. 4 is a schematic configuration diagram of a magnet body holding portion of the magnetic coupling of the third embodiment. In the magnetic coupling of the third embodiment shown in FIG. 4, the magnetic viscoelastic fluid holding portions 45 and 46 of the magnet body holding portions (cones) 43 and 44 are connected to the partition wall 18 side of the drive shaft 12 and the driven shaft 11. It provided around the convex, in which the magnet holding member (corn) first magnet body ₁₅ in the 43 and 44 _1, 15 _2, 15 _3, 16 1, 16 ₂ has to be close. By doing so, because the first magnet body _{15 1,} 15 _2, 15 _3, 16 1, 16 ₂ can be brought close, it is possible to provide a stronger magnetic coupling.

FIG. 5 is a schematic configuration diagram of a magnet body holding portion of the magnetic coupling according to the fourth embodiment. In the magnetic couplings of Examples 1 to 4 described so far, the second magnet body 26 for holding the magnetic viscoelastic fluid has a magnet body as shown in FIGS. 1 (B) and 2 (A). The holding portions (cones) 13 and 14 were provided. However, the magnet body holding portions 53 and 54 of the magnetic coupling of the fourth embodiment shown in FIG. 5 do not have the second magnet body 26, and instead, the magnet body holding portions 53 and 54 are formed of a magnetic material. . The first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , and 16 ₂ for magnetic coupling are all made to have the same polarity in each of the magnet body holding parts (cones) 13 and 14, and the magnet body holding part As indicated by arrows in 53 and 54, the magnetic forces of the first magnet bodies 15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , and 16 ₂ pass through the magnet body holding parts 53 and 54 and concentrate on the axial center part. Thus, the magnetic viscoelastic fluid 17 can be held.

  In this manner, when the second magnet body 26 for holding the magnetic viscoelastic fluid is provided in the magnet body holding portions (cones) 13 and 14, the positions thereof are the driven shaft 11 and the driving shaft 12. It is necessary to prepare a donut-shaped magnet body because it is at a certain position, or to provide the driven shaft 11 and the driving shaft 12 before the second magnet body, but it is necessary to prepare such a special magnet In addition, it is not necessary to shorten the driven shaft 11 and the driving shaft 12.

  According to the present invention, the coupling loss between the drive shaft and the driven shaft in the magnetic coupling can be reduced, and a long-life magnetic coupling can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS (A) of the magnetic coupling Example 1 which concerns on this invention is (A) the structure outline of a principal part, (B) is a figure of an example of the arrangement | positioning state of the magnet body for torque transmission. In Example 1 of the magnetic coupling according to the present invention, (A) is an enlarged schematic diagram of a magnet body holding part holding a magnetic viscoelastic fluid, and (B) is a driving shaft and a driven shaft by the magnetic viscoelastic fluid. It is a figure for demonstrating the principle which produces the thrust direction stress of the direction which separates each from a partition. It is a structure outline of the magnet body holding part of Example 2 of the magnetic coupling which becomes this invention. It is a structure outline of the magnet body holding part of Example 3 of the magnetic coupling which becomes this invention. It is the structure outline of the Example which used the magnetic force of the 1st magnet body for torque transmission as the magnetic force of the magnet body holding part in the magnetic coupling which becomes this invention. 3 is a schematic configuration of an experimental apparatus in which a thrust stress in a direction in which a driving shaft and a driven shaft are separated from a partition wall of a magnetic coupling according to the present invention is measured. It is a graph of the rheological characteristic measured by the experimental apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic coupling 11 Driven shaft 12 Drive shaft 13, 14 Magnet body holding part (cone)
15 ₁ , 15 ₂ , 15 ₃ , 16 ₁ , 16 ₂ First magnet body 17 Magneto-viscoelastic fluid 18 Partition wall 19 Rotating direction of driven shaft 20 Rotating direction of driving shaft 26 Second magnet body 21 Centrifugal force 22 Gravity 23 Surface tension 24 Magnetic body force (magnetic force)
25 Thrust direction stress

Claims (8)

A drive shaft and a driven shaft that are opposed to each other across a partition wall made of a non-magnetic material and are arranged on an axis,
A plurality of first magnet bodies that are arranged at a predetermined distance in the radial direction from the shaft center of each of the drive shaft and the driven shaft and that are opposed to each other as polarities attracting each other, and each of the drive shaft and the driven shaft In a magnetic coupling comprising a magnet body holding portion that is provided and holds the first magnet body,
A second magnet body disposed in a region around the axial center in each of the magnet body holding portions; and a magnetic viscoelastic fluid held by the magnetic force of the second magnet body, and the magnet body holding portion. Is formed so that the separation distance from the partition wall increases as the distance from the partition wall side axis increases at least partially in the radial direction.
The magnet body holding portion, and one end of the partition wall-side axis, is formed in an arc shape in the circumferential direction, the centrifugal force of the magnetic viscoelastic fluid by rotation of the magnet holding member and the surface tension and the second magnet Due to the resultant force with the magnetic force of the body, a low-axis load is applied due to the thrust direction stress in the direction in which the drive shaft and the driven shaft are separated from the partition wall against the pulling force of the first magnet body. Magnetic coupling characterized by.   The magnetic viscoelastic fluid is set so that the resultant force of the surface tension and the magnetic force of the second magnet body is greater than the resultant force of centrifugal force and gravity generated by the rotation of the magnetic viscoelastic fluid. The magnetic coupling according to claim 1. The drive shaft and the driven shaft, which are opposed to each other with a partition made of a non-magnetic material interposed therebetween, attract each other at a predetermined distance in the radial direction from the shaft center of each of the drive shaft and the driven shaft. Magnetic coupling comprising a plurality of first magnet bodies arranged in a relative relationship as polarities, and a magnet body holding portion that is provided on each of the drive shaft and the driven shaft and holds the first magnet body In
A magnetic viscoelastic fluid held by a magnetic force in the region around the axial center of the magnet body holding portion;
Each of the magnet body holding portions is configured such that the separation distance from the partition wall increases as the distance from the partition wall increases in the radial direction with the partition wall side axis as an apex at least partially. Is formed in an arc shape in the circumferential direction, and is configured to generate a magnetic force by the first magnet body in the region around the axis using a magnetic body,
Against the attractive force of the first magnet body due to the resultant force of the centrifugal force and surface tension of the magnetic viscoelastic fluid due to the rotation of the magnet body holding part and the magnetic force of the area around the axis of the magnet body holding part. A magnetic coupling having a low axial load caused by a thrust direction stress in a direction in which the generated drive shaft and driven shaft are separated from the partition wall.   The magnetic viscoelastic fluid is selected so that the resultant force of the surface tension and the magnetic force in the region around the axis of the magnet body holding portion is greater than the resultant force of centrifugal force and gravity generated by the rotation of the magnetic viscoelastic fluid. The magnetic coupling according to claim 3, wherein the magnetic coupling is provided.   5. The magnetic coupling according to claim 1, wherein the magnet body holding portion has a conical shape with the partition wall side axis as an apex. The magnetic coupling according to any one of claims 1 to 5 , wherein the magnet body holding portion is in contact with the partition at a plurality of positions including one or an annular portion in a non-rotating state. The magnetic coupling according to claim 6 , wherein a position where the magnet body holding portion contacts the partition wall in a non-rotating state is the partition wall side axis. The magnet body holding portion is formed in an arc shape with the partition side axial center as one end, and the portion where the magnet body holding portion contacts the partition wall in a non-rotating state of the driving shaft and the driven shaft is the arc shape The magnetic coupling according to claim 6 , wherein the magnetic coupling is provided in an annular portion.

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